INTERVIEW with Gillen D’Arcy Wood — The Wake of HMS Challenger

Gabrielle Birchak/ October 21, 2025/ Archive, Modern History

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PODCAST TRANSCRIPTS

GABRIELLE BIRCHAK

Today’s pod­cast is a very spe­cial pod­cast because I’m going to be inter­view­ing Pro­fes­sor Gillen D’Ar­cy Wood, the author of The Wake of the HMS Chal­lenger. And by the time you are done lis­ten­ing to this, you’re gonna fall in love with the oceans and you’re going to want to know all about this amaz­ing jour­ney of the HMS Chal­lenger and how their research estab­lished the base­line for what we know about the oceans today. The sto­ry of the HMS Chal­lenger is amaz­ing and Gillen’s sto­ry takes a real­ly unique bio­cen­tric view on our 19th cen­tu­ry oceans.

Before I begin my inter­view with Gillen D’Ar­cy Wood, here is a brief back­ground on the HMS Chal­lenger. The HMS Chal­lenger set sail in Decem­ber of 1872 and tra­versed across and back the ocean end­ing its jour­ney in May of 1876. So we’re cel­e­brat­ing a hun­dred and fifty years of the HMS Challenger.

And if the name Chal­lenger sounds famil­iar, that is because NASA named its sec­ond orbiter after this Roy­al Navy ves­sel. It was a sym­bol­ic trib­ute to a sea ves­sel that left a lega­cy of excit­ing dis­cov­er­ies and enchant­i­ng explo­rations. To seek and dis­cov­er was the mis­sion of the HMS Challenger.

The goal of the sci­en­tists on board was to under­stand the mys­ter­ies of the deep sea. So this book is a beau­ti­ful inter­weav­ing of sto­ries that light­ly focus on the sci­en­tists on board but most­ly enlight­en the read­ers on the char­ac­ter­is­tics of the sea crea­tures that they dis­cov­ered. Gillen D’Ar­cy Wood impec­ca­bly weaves the sto­ries of the 19th cen­tu­ry with our cur­rent under­stand­ing of the ocean today and imple­ments the impor­tance of ocean conservation.

Gillen D’Ar­cy Wood is the Scha­ef­fer Pro­fes­sor of Lib­er­al Arts and Sci­ences at the Uni­ver­si­ty of Illi­nois Urbana-Cham­paign. He is the author of the award-win­ning book Tamb­o­ra, The Erup­tion That Changed the World, writ­ten in 2014, and a his­to­ry of ear­ly Antarc­tic explo­ration, Land of Won­drous Cold, writ­ten in 2020. His new book, The Wake of the HMS Chal­lenger, How a Leg­endary Vic­to­ri­an Voy­age Tells the Sto­ry of Our Ocean’s Decline, marks the 150th anniver­sary of the famous voy­age that gave birth to mod­ern oceanog­ra­phy and calls atten­tion to many threats that our oceans and the ocean life and the habi­tats face today.

So, let’s have a con­ver­sa­tion with Gillen D’Ar­cy Wood, the author of The Wake of the HMS Chal­lenger. Gillen, it is an absolute hon­or to have you on Math Sci­ence His­to­ry. I’m real­ly look­ing for­ward to this interview.

Let’s jump right into the ques­tions. In the sub­ti­tle of your book, you call HMS Chal­lenger’s voy­age around the world leg­endary. I watched a video of you talk­ing about the Chal­lenger where you talk about shift­ing base­line syn­drome or gen­er­a­tional amnesia.

And that being said, I’m won­der­ing, has its mem­o­ry fad­ed a bit after 150 years and why should we return to think­ing about it now?

GILLEN D’ARCY WOOD

Yes, so here we are 150 years after the birth of oceanog­ra­phy with this voy­age of HMS Chal­lenger that trav­eled the three and a half years across all oceans of the globe. And it’s a time for reflec­tion, ret­ro­spec­tion on the impor­tance of that voy­age. And my goal in writ­ing the book was to show that it’s not a mat­ter of his­tor­i­cal curios­i­ty only, that in fact Chal­lenger has a fresh and urgent sto­ry to tell us.

And that is that it gives us this unique snap­shot of the oceans as they were 150 years ago. And we can com­pare what Chal­lenger saw in its three-year voy­age to how our oceans are today. And there have been a great many changes that I talk about in the book.

And the read­er is able to both relive the voy­age as it was and the oceans as they were in the 1870s and also have a cold hard look at our oceans today and how they’ve changed.

GABRIELLE BIRCHAK

And they cer­tain­ly have changed. What would you say are the great achieve­ments of the Chal­lenger expe­di­tion? I’m curi­ous to know because there’s so much material.

How did it launch the ocean sci­ences as we know them today?

GILLEN D’ARCY WOOD

It’s remark­able if you think that this three and a half year expe­di­tion around the world was launched with real­ly just a one-page research pro­pos­al. And they con­vert­ed a war­ship and while the achieve­ments of HMS Chal­lenger are leg­endary, they brought back in in bot­tles and crates 5,000 new marine crea­tures unknown to sci­ence. They record­ed tem­per­a­ture data at the sea sur­face and at depth all across the globe.

They mea­sured deep-sea cur­rents. They mapped the seafloor and real­ly paved the way for the mod­ern the­o­ries of plate tec­ton­ics. And they plunged the Mar­i­ana Trench which is the deep­est part of the world’s ocean.

So there’s so many dif­fer­ent feats of dis­cov­ery that we owe to HMS Chal­lenger. As a writer it was a daunt­ing prospect to con­front their 50 vol­umes of data that they brought back with them and to find the sto­ry that I want­ed to tell.

GABRIELLE BIRCHAK

So that being said, as it launched the ocean sci­ences that we know today, I love that in your book you have main char­ac­ters and they’re not who you expect. You say that you want­ed to take a fresh take on Chal­lenger and you want­ed a bio­cen­tric nar­ra­tive. What do you mean by that and why do you think that that bio­cen­tric nar­ra­tive is impor­tant today?

GILLEN D’ARCY WOOD

So the Chal­lenger sto­ry has been told many times over the last 150 years. But the focus has always been on real­ly the human ele­ment in the voy­age of telling the sto­ry of the sci­en­tists and their expe­ri­ences. I want­ed to tell that sto­ry and retell it but I want­ed to shift the focus real­ly to the marine life itself and to make, as you say, to make the marine crea­tures the stars of the show and have the sci­en­tists real­ly just be a kind of vehi­cle for telling the sto­ries of the amaz­ing crea­tures that inhab­it the deep sea.

So I chose as the focus for every chap­ter a spe­cif­ic ani­mal or fish that we could focus on and to tell its his­to­ry, to tell its biog­ra­phy, its deep evo­lu­tion­ary his­to­ry, but also its prospects for sur­vival in our own mod­ern 21st cen­tu­ry oceans in which a marine life faces so many threats. So I do think of this idea of bio­cen­tric sto­ry­telling as sort of an impor­tant chal­lenge for us in the mod­ern era to shift our focus away from our own human expe­ri­ence exclu­sive­ly and real­ly ori­ent our­selves toward the ani­mals, the plants and ani­mals with whom we share our planet.

GABRIELLE BIRCHAK

That was your pri­ma­ry inspi­ra­tion for focus­ing on the char­ac­ters of the book. Would you say that’s the case?

GILLEN D’ARCY WOOD

Oh, absolute­ly. So I decid­ed to orga­nize the chap­ters, for instance. I have 13 chap­ters and I decid­ed that each chap­ter should fea­ture a par­tic­u­lar aspect or crea­ture in the oceans.

And so I have a chap­ter on coral reefs, I have a chap­ter that fea­tures the sea­horse, anoth­er that fea­tures an absolute­ly, exquis­ite­ly beau­ti­ful deep-sea sponge. And my final chap­ter, which is one of my favorites, is on the green tur­tle. And in each case, I give an up-close-and-per­son­al nar­ra­tive about the crea­ture and what the chal­lenger saw, how they saw and described, say, the sea­horse or the sponge, and then the chal­lenges that the ani­mal faces today liv­ing in our anthro­pogenic oceans.

GABRIELLE BIRCHAK

I thought that was just bril­liant because I loved that you focused on the crea­tures of the sea because they’re so very valu­able. That was also inspir­ing for the read­er. I want­ed to know how the research on the HMS Chal­lenger is dif­fer­ent than oth­er research boats that helped estab­lish the base­line data for all future ocean research because their jour­neys were extensive.

How did it estab­lish that baseline?

GILLEN D’ARCY WOOD

So real­ly noth­ing com­pares in scale and scope to the voy­age of the HMS Chal­lenger, which is why we go back to it again and again. The fact that they con­vert­ed a Roy­al Navy war­ship and turned it into a float­ing marine sci­ence acad­e­my, they appoint­ed six sci­en­tists, there’s a crew of 250 men, they sailed for three and a half years, no expense was spared, they had the lat­est cut­ting-edge tech­nol­o­gy avail­able to them, and of course what they had was the, most impor­tant­ly, was the infra­struc­ture of the British Empire. They were able to sail from port to port, they were able to go from Por­tu­gal to Madeira to Brazil to South Africa to Antarc­ti­ca to Mel­bourne in Aus­tralia to the Philip­pines and across the Pacif­ic, and at every point in the jour­ney they were able to make use of the resources of the colo­nial ports that were run by the British.

So in a way it was a one-off endeav­our that has nev­er again been repeat­ed, and in fact there was not a research jour­ney of com­pa­ra­ble pro­por­tions to the Chal­lenger until well into the 20th cen­tu­ry. So if you think about that, the data that we have from the Chal­lenger in the 1870s is this unique snap­shot of the oceans, and we don’t have any­thing as detailed or tex­tured until well into the 20th cen­tu­ry, and it’s actu­al­ly true that some places that the Chal­lenger vis­it­ed were so remote that they have nev­er been vis­it­ed by a research expe­di­tion, and so that there are some crea­tures that they found in parts of the ocean that have, where the Chal­lenger spec­i­men remains the sole data point for that crea­ture. For sev­er­al starfish, for exam­ple, the one known exam­ple of the species is from the Chal­lenger voy­age, which is remark­able when you think about it.

GABRIELLE BIRCHAK

It’s very remark­able con­sid­er­ing that was, this is the anniver­sary, the 150th anniver­sary of the HMS Chal­lenger. That data is 150 years old. It is a foun­da­tion­al baseline.

GILLEN D’ARCY WOOD

Exact­ly, and unique, yes.

GABRIELLE BIRCHAK

I under­stand that they left a very vast archive behind the explo­ration, and isn’t it 50 vol­umes of data and research, per­son­al diaries and logs of the sci­en­tists and the ship’s offi­cers? How many years did it take you to write this phe­nom­e­nal book?

GILLEN D’ARCY WOOD

It took me about five years, and you’re right that these 50 vol­umes of data was a spe­cial edi­tion, lim­it­ed edi­tion, only there are some lucky uni­ver­si­ties and muse­ums around the world that have the full set of 50 vol­umes, each of them the size of the Guten­berg Bible. I real­ized very ear­ly on that it was not pos­si­ble to pro­vide an absolute­ly com­pre­hen­sive treat­ment of the voy­age and all its dis­cov­er­ies. What I decid­ed to do for the read­er was I want­ed the read­ers to expe­ri­ence the whole jour­ney, every ocean and con­ti­nent that they trav­eled across.

I want­ed to give a high­light reel of their dis­cov­er­ies, and I also want­ed to immerse the read­er in the dai­ly life aboard a Vic­to­ri­an war­ship that would be con­vert­ed to a research ves­sel to give the read­er the sights, the sounds, and the smells of what it was like every day to send down the trawl and to bring up a kind of cor­nu­copia of marine life, and to try to recap­ture for us 150 years lat­er the expe­ri­ence of won­der that the Chal­lenger sci­en­tists had on a dai­ly basis by encoun­ter­ing crea­tures that they’d human­ized, you know, they’d nev­er seen before. A lot of it, of course, was a puz­zle to them or a mys­tery or an enig­ma, and try­ing to cap­ture that incred­i­ble era of curios­i­ty in nature at the begin­nings of what we now know today as mod­ern marine science.

GABRIELLE BIRCHAK

What were the hard­est deci­sions you had to make as a writer as you com­piled this into 13 chapters?

GILLEN D’ARCY WOOD

Obvi­ous­ly, a lot was left out. There’s a lot left on the cut­ting room floor, and in choos­ing the crea­tures to focus on, I cre­at­ed a kind of Venn dia­gram in my head where I need­ed the crea­ture I chose to be charis­mat­ic in some way, an inter­est­ing crea­ture, one for which there’s a paper trail. There’s a sci­en­tif­ic lit­er­a­ture on the crea­ture that I could talk about, be it some par­tic­u­lar species of coral, or a spe­cif­ic microplank­ton, or again, you know, the green turtle.

The third fac­tor was a kind of threat or endan­ger­ment that the ani­mal was under. Think­ing about these three things, that they’re charis­mat­ic, that there’s sci­en­tif­ic research done on them, but they’re also under threat today. It was by cre­at­ing a small­er class of crea­tures that I could talk about that would focus in real­ly on ani­mals in the oceans that best rep­re­sent the cur­rent ocean cri­sis and the chal­lenges that we face in try­ing to viable habi­tats for all the ani­mals in the ocean.

GABRIELLE BIRCHAK

You cer­tain­ly accom­plish that. You’ve def­i­nite­ly immersed the read­er in the entire envi­ron­ment, and the smells, and even the char­ac­ter­is­tics of each of the sea ani­mals that you’re talk­ing about. In one chap­ter, you talk about the brooch clams and the hairy mus­sels, and you had not­ed that Fran­cois Per­ron dis­cov­ered a trigo­nia-like shell, which showed that the trigo­nia shell was not extinct.

And I know back in the Vic­to­ri­an era, back in the 1800s, there had been dis­cus­sions and debate about extinc­tion, but as I under­stand it, it was the 19th cen­tu­ry mind­set that our oceans were inex­haustible. Did the dis­cov­er­ies on the HMS help to cre­ate that bridge to our cur­rent under­stand­ing of ocean conservation?

GILLEN D’ARCY WOOD

It’s cer­tain­ly true that they did­n’t have our mod­ern view of endan­gered habi­tats, and that the human impact on ecosys­tems could be so intense as we know today. So they were in a way gift­ed with a kind of obliv­i­ous­ness with regard to the human foot­print on the ocean. And you men­tioned extinction.

Well, extinc­tion in the 19th cen­tu­ry, or the the­o­ry of extinc­tion, the idea that ani­mals could pass into and out of exis­tence, this idea was still con­tro­ver­sial in the 19th cen­tu­ry. There were cer­tain­ly argu­ments or pro­po­nents of the idea that extinc­tion was, a benev­o­lent god would not allow crea­tures once cre­at­ed to lapse into extinc­tion. So this was still a con­tro­ver­sial issue.

And you men­tioned the famed trigo­nia shell, which had been dis­cov­ered in fos­sil form and was held up as an exam­ple of the con­ti­nu­ity of cre­ation, the con­ti­nu­ity of life, the fact that a liv­ing trigo­nia shell could be found. But also, and this is where the trigo­nia is so inter­est­ing, it also served poten­tial­ly as a proof of Dar­win­ian evo­lu­tion in that dif­fer­ences could be shown between the ancient fos­silized trigo­nia and the mod­ern liv­ing trigo­nia. And when we look back to Chal­lenger, we can see how Chal­lenger sailed real­ly under the shad­ow of Dar­win, if you like.

And one of the prin­ci­pal rea­sons for Chal­lenger set­ting out was for the pur­pose of dis­cov­er­ing poten­tial miss­ing links in the deep sea. The Vic­to­ri­ans, unlike us, the Vic­to­ri­ans looked at the deep sea as a kind of muse­um of ancient life. They pre­sumed that the deep sea was unchang­ing, and it would be a kind of muse­um of mon­sters from the past.

Now, one of the inter­est­ing out­comes of the expe­di­tion was that it did­n’t real­ly dis­cov­er a kind of muse­um trove of ancient forms of life in the deep sea. And we now know that that’s because the deep sea is not ancient and unchang­ing in the way that they thought it was. But with all the sort of con­tro­ver­sy and the Dar­win­ian atmos­phere sur­round­ing the voy­age, and the fact that they set out in that Dar­win­ian moment, I think from our point of view, 150 years lat­er, the voy­age turned into some­thing dif­fer­ent entirely.

When we look back at it, we see it as the first ever inven­to­ry of the oceans. It’s an extra­or­di­nary cat­a­logue of tens of thou­sands of crea­tures, which they were able to geo­graph­i­cal­ly locate and iden­ti­fy and describe in their nat­ur­al habi­tats. And as such, it’s this incred­i­ble infor­ma­tion base for us to see what our oceans looked like on the eve of indus­tri­al­iza­tion and before all the accu­mu­la­tion of our mod­ern impacts on the oceans.

GABRIELLE BIRCHAK

Stick around. After the break, we’re going to learn about Dar­win’s inspi­ra­tion for the HMS Chal­lenger and how even Vic­to­ri­ans were sen­si­tive to the idea of how ocean con­di­tions could affect life in the oceans. Would you say that Dar­win’s dis­cov­er­ies were an inspi­ra­tion for the HMS Challenger?

GILLEN D’ARCY WOOD

I believe so. So if we look at the dates, the Ori­gin of Species was pub­lished in 1859 and con­tro­ver­sy raged through the 1860s about Dar­win’s the­o­ries. Dar­win him­self point­ed to the deep sea as the place in which his the­o­ries might be ver­i­fied or not, where miss­ing links might be found.

The debate real­ly cen­tered on whether it could be shown that crea­tures changed over time and could we find exam­ples of evo­lu­tion in action. The Chal­lenger def­i­nite­ly set out with the six sci­en­tists aboard were very excit­ed at the pos­si­bil­i­ty that they might make sci­en­tif­ic his­to­ry by bring­ing up exam­ples of miss­ing links from the deep sea and begin a new chap­ter in evo­lu­tion­ary sci­ence. From that point of view, the results of the expe­di­tion were equiv­o­cal, it must be said, because they had why they brought with them a mis­con­cep­tion about the deep sea.

We now know that with mod­ern tec­ton­ic plate the­o­ry, we know that the seafloor, the old­est por­tions of the seafloor are only mil­lions of years old, cer­tain­ly not tens of mil­lions or let alone bil­lions of years old, which is how they imag­ined to be. So we know that there is geo­log­i­cal turnover in the deep sea and there­fore bio­log­i­cal turnover as well, but they had none of that infor­ma­tion. It’s quite remark­able when read­ing the sum­maries of their reports, how clear a pic­ture they did have of the oceans and how many of their ideas are still holed up today.

They believed that, as we do, that envi­ron­ment is very impor­tant to the habi­tats of crea­tures and to their prospects for sur­vival and also to their evo­lu­tion. So they were par­tic­u­lar­ly sen­si­tive to the idea of how ocean con­di­tions might affect life in the oceans. That basic idea was one that the Vic­to­ri­ans had and were par­tic­u­lar­ly atten­tive to, which is why, along with all of the infor­ma­tion about marine life, they also took great care to bring back reams of tem­per­a­ture data and data regard­ing ocean chem­istry, which is so valu­able to us today.

If you can imag­ine, we now in a peri­od of ris­ing ocean tem­per­a­tures, we can look back to the 1870s thanks to the Chal­lenger and see a kind of base­line of ocean tem­per­a­ture con­di­tions and mea­sure the amount of change that has hap­pened over 150 years. So in that sense, the Chal­lengers were very sen­si­tive to the idea of envi­ron­men­tal con­di­tions dri­ving life on earth and life in the oceans. They were cer­tain­ly very mod­ern in their thinking.

GABRIELLE BIRCHAK

Your book is a sci­en­tif­ic dis­cov­ery sto­ry full of nat­ur­al won­ders of the sea. It also has a very pow­er­ful con­ser­va­tion mes­sage about how much our oceans have changed since the days of the HMS Chal­lenger. What are some of the major threats to our oceans that you high­light in the book?

GILLEN D’ARCY WOOD

Yes, our oceans are cer­tain­ly in cri­sis and suf­fer­ing under mul­ti­ple strains and stress­es. I think the three main issues con­fronting the oceans today are over­fish­ing, ocean warm­ing, and also plas­tic pol­lu­tion. I take them, each of the three of these, one at a time and in a chap­ter that I write about the Chal­lengers’ vis­it to Japan and their encounter with the infant Japan­ese salmon fish­ing indus­try, I talk about how our seafood con­sump­tion over the 20th cen­tu­ry has increased eight or ten­fold, par­tic­u­lar­ly since the Sec­ond World War.

90% of larg­er fish in the high­er lev­els of the food chain, think­ing salmon and tuna and cod, have been deplet­ed from the oceans. Even since the 1980s, we’ve lost 40% of fish and even 20% of inver­te­brates, such as scal­lops. With that over­fish­ing is the impacts of deep-sea trawl­ing tech­nol­o­gy on the seabed.

We have rich­er ecosys­tems of corals and sponges, etc., trawled over again and again by these large nets the size of foot­ball fields and turned into sandy deserts. I’d say that if there were a num­ber one prob­lem, it were prob­a­bly that. But of course, there’s a lot of press that we read now about the effects of warm­ing on the oceans.

And right now, I’m talk­ing to you from the Mid­west, where we’re expe­ri­enc­ing a drought. And those drought con­di­tions can be con­nect­ed all the way to what sci­en­tists are call­ing a marine blob, a great heat blob in the Pacif­ic Ocean, where thou­sands of square miles of ocean are up to 10 degrees Fahren­heit warmer than the aver­age. And this is affect­ing our weath­er systems.

And if the marine blob, if marine heat waves are pow­er­ful enough to impact weath­er in the Mid­west, think what it must be like for the crea­tures who are liv­ing in the oceans them­selves. An increased warmth wreaks hav­oc with the metab­o­lism of the fish, who have to expend much more ener­gy cool­ing them­selves, main­tain­ing their body tem­per­a­ture. It affects their repro­duc­tion cycles.

It dam­ages or com­pro­mis­es their food sources, plank­ton and kelp, etc. And the larg­er demo­graph­ic and geo­graph­ic issue is that warmer waters dri­ves these fish pop­u­la­tions in the direc­tion of the poles. They’re seek­ing cool­er waters, seek­ing their nat­ur­al habitat.

And of course, because our plan­et is a sphere, they will even­tu­al­ly run out of room as they attempt to migrate for their sur­vival to the poles. The last thing that I would men­tion, the last of sort of, I guess, the three horse­men of the ocean apoc­a­lypse would be microplas­tics. And we’ve all heard about the Pacif­ic Garbage Patch and the Atlantic Garbage Patch, these mas­sive gyres of plas­tic cir­cu­lat­ing in the mid­dle of the oceans, the size of Texas.

These cap­ture the head­lines. Worse still, even than the impact of those is microplas­tics, the way these deposit­ed plas­tics in the ocean break down over time to form micro or even nano-sized plas­tics. Now these enter into the marine food chain.

They dis­trib­ute them­selves through ocean sed­i­ments and in the water col­umn. They’re mis­tak­en for food, they’re ingest­ed. And we now know from sam­pling a wide vari­ety of ocean crea­tures from tur­tles and sharks all the way down to the small­est of fish and crus­taceans that there are poly­mers and plas­tics in the stom­achs of almost all liv­ing crea­tures in the sea now.

And we’re only just begin­ning to sort of grasp what the impli­ca­tions of the plas­tic infes­ta­tion of the sea will be on marine life, but also for us, for humans as apex con­sumers at the top of the ocean food chain.

GABRIELLE BIRCHAK

So you’re say­ing that we are just only at the begin­ning of under­stand­ing the dam­ages that microplas­tics are doing to our ocean?

GILLEN D’ARCY WOOD

Yes, it’s real­ly new sci­ence in the last 10 years or so. There was a very impor­tant paper pub­lished that attempt­ed to cal­cu­late the amount of plas­tics since the 1950s had been deposit­ed in the ocean and what we were able to observe on the coasts and in the sea sur­face and the great plas­tic garbage patch­es and realised there was an enor­mous short­fall. The plas­tic that could be account­ed for, say in the garbage patch­es in the ocean gyres and on the coasts and on the beach­es, bare­ly account­ed for half of all ocean plas­tic that must have entered the sea.

That’s as much as five tril­lion pieces of plas­tic since 1950. So this prompt­ed a search for where it might be and what might have hap­pened to all the plas­tic. And it was dis­cov­ered in the sea floor and in the water col­umn in the form of microplastics.

So now, yeah, this new fron­tier of sci­ence in try­ing to under­stand, well, what are microplas­tics doing to the oceans?

GABRIELLE BIRCHAK

Did­n’t they find a plas­tic bag at the bot­tom of the Mar­i­ana Trench?

GILLEN D’ARCY WOOD

That is absolute­ly true. I write about that in the book. And the deep­est part of the Mar­i­ana Trench, the deep­est trench in the ocean, five miles deep, dis­cov­ered real­ly quite freak­ish­ly by HMS Chal­lenger in 1874.

And sub­mersibles have been down to the Chal­lenger Deep, includ­ing James Cameron in his own pilot­ed sub­mersible. And they have found there, even in this deep­est por­tion of the sea, deep­er below the sea than the Mount Ever­est ris­es above the earth, they’ve found beer cans and plas­tic bags, cables and toi­letries, pack­ag­ing, every­thing that you could imagine.

GABRIELLE BIRCHAK

Wow, that’s heart­break­ing. That’s why I real­ly appre­ci­ate your book, because it real­ly tells us the impor­tance of the val­ue of sea life and the beau­ty of it, as well as the val­ue in con­serv­ing it all.

GILLEN D’ARCY WOOD

Yeah. And I think that this is such an impor­tant his­tor­i­cal moment for us to turn our atten­tion toward the oceans. I mean, we are ter­res­tri­al beings, if you think of it.

And of course, our bias­es are toward the land that we inhab­it, and we’ve increas­ing­ly dom­i­nat­ed over time. And the oceans can be rel­e­gat­ed to a kind of after­thought for us. I want­ed my book to par­tic­i­pate in what I think is a grow­ing move­ment, a turn toward the oceans.

There are shelves full nowa­days of books about the oceans and ocean life. And I think we are at a moment where we are turn­ing our atten­tion to 70% of our plan­et. We are a watery, aque­ous, blue planet.

We need to remind our­selves of that.

GABRIELLE BIRCHAK

Five years writ­ing this book, what was your favorite part of the story?

GILLEN D’ARCY WOOD

My favorite part of the book, I think, was the end, my final chap­ter, which is about the green tur­tles. And in a way, the his­to­ry of the green tur­tles over the last 500 years is sort of the his­to­ry of human impacts on the plan­et real­ly summed up the fact that in the ear­ly days of colo­nial­ism in the Amer­i­c­as, green tur­tle meat was an impor­tant pro­tein to the plan­ta­tion economies of the West Indies, because it was cheap, plen­ti­ful pro­tein source. But the num­bers, the sheer num­bers of green tur­tles har­vest­ed and con­sumed reduced their orig­i­nal pop­u­la­tion from prob­a­bly 60 or 70 mil­lion down to only sev­er­al hun­dred thousand.

So it’s a near extinc­tion threat fac­ing the green tur­tles up and into the 20th cen­tu­ry. But since the mid­dle of the 20th cen­tu­ry, when the prospects for extinc­tion of the green tur­tles became appar­ent, there have been a very suc­cess­ful series of reg­u­la­tions and con­ser­va­tion efforts focused on the green tur­tles that have seen them rebound from their near extinc­tion num­bers. And they’re now begin­ning to flour­ish again in both the Atlantic and the Pacif­ic Oceans.

And the final chap­ter of my book takes the read­er to their favorite breed­ing ground in the mid­dle of the Atlantic Ocean on a tiny vol­canic island called Ascen­sion Island and shows how the ban­ning of tur­tle har­vest­ing and the pro­tec­tion of the beach­es where the green tur­tle females come to lay their eggs and bury them to repro­duce. The pro­tec­tion of these beach­es has enabled these crea­tures to, these won­der­ful rep­tiles, to bounce back. The sto­ry of the green tur­tle shows us that there is a base­line resilience in ocean life and that all these crea­tures need is a chance, is a kind of fight­ing chance to bounce back.

And it’s an oppor­tu­ni­ty for us, you know, as the human com­mu­ni­ty to coop­er­ate and to cre­ate new bonds with these ani­mals we so admire and have so relied on in the past and to help them flour­ish with us, you know, in the world rather than see­ing our rela­tion­ship to the world as sort of pure­ly exploita­tive and con­sum­ing with­out thought. The idea that we can sus­tain­ably live with these ani­mals and move into a bet­ter future together.

GABRIELLE BIRCHAK

It’s a beau­ti­ful chap­ter. It’s so touch­ing and you’re right, giv­ing them a fight­ing chance and then cre­at­ing new bonds also cre­ates a lev­el of hope that we can do this with the rest of the plan­et as well.

GILLEN D’ARCY WOOD

I think that’s true that I want­ed my book to be the full spec­trum from the dark to the light. That yes, there has been tragedies in our oceans but it’s not too late. There’s still places of extra­or­di­nary enchant­ment and wonder.

There are crea­tures fight­ing for their sur­vival. It’s an extra­or­di­nary real-world aquar­i­um of won­der­ful life. The chal­lenge now is for us to learn and relearn how to val­ue these ani­mals and their habi­tats and with the sci­ence and the tech­nol­o­gy that we have today to apply that in pre­serv­ing those habi­tats and ensur­ing that these crea­tures have the space that they deserve to thrive.

GABRIELLE BIRCHAK

If peo­ple want to read your book, where can they find it?

GILLEN D’ARCY WOOD

In any favorite online pur­vey­or, it’s cer­tain­ly avail­able on Ama­zon and online, any­where you would like to pur­chase it. It should be avail­able in book­stores from the Octo­ber the 21st. If you are liv­ing in the Unit­ed King­dom or in Europe, you’ll have to wait until January.

GABRIELLE BIRCHAK

For my lis­ten­ers right now in the Unit­ed States, you can go out today, Octo­ber 21st and pur­chase the book. I high­ly rec­om­mend it. It’s real­ly good.

GILLEN D’ARCY WOOD

Thanks, Gabrielle. It was a great plea­sure. It was an extra­or­di­nary jour­ney for me as a writer to weave the tale and to try to bring the 19th cen­tu­ry world alive and to show its urgent rel­e­vance to us today.

Real­ly, the time between our era and theirs is real­ly just the blink of an eye in bio­log­i­cal terms, in evo­lu­tion­ary terms, in the terms of the life on earth. We need to be remind­ed of that. We’re so har­ried and harassed by the present.

We tend to com­press our idea of time into just what’s imme­di­ate­ly impor­tant to us. I think this is an oppor­tu­ni­ty read­ing this book to think that, well, back the 19th cen­tu­ry is still, in a way, present to us and alive and important.

GABRIELLE BIRCHAK

Before we go, what are your last thoughts?

GILLEN D’ARCY WOOD

I think my last thoughts are that by revis­it­ing the 1870s and revis­it­ing this extra­or­di­nary one-off voy­age, reliv­ing that nar­ra­tive with them is a chance for our­selves as vic­ar­i­ous trav­el­ers to expe­ri­ence an enchant­ment of nature and the enchant­ment of the oceans, to relive with them the won­der and the amaze­ment of their dis­cov­er­ies. I think that here in the nat­ur­al world and on a day-to-day basis, we’re con­front­ed with data and infor­ma­tion about envi­ron­men­tal crises that we need to also look, explore beyond the data and to rethink at an exis­ten­tial and emo­tion­al lev­el what our rela­tion­ship with the nat­ur­al world is, was, and can be. As I say in my intro­duc­tion to the book, in order to save the world, we need to re-enchant the world.

We need to redis­cov­er a more pri­mal, sym­pa­thet­ic con­nec­tion with the world around us, with its crea­tures, and that on land and on the oceans. I think the pur­pose of my book is to cre­ate that kind of world, to immerse the read­er in a world where a liv­ing, thriv­ing ocean and human par­tic­i­pa­tion in that world is pos­si­ble and avail­able to us.

GABRIELLE BIRCHAK

I love that idea, that to tru­ly save the world, we have to fall in love with it again and to be re-enchant­ed with it. That is real­ly pro­found. Gillen, thank you for remind­ing us of that and for spend­ing time with me and my lis­ten­ers here at Math Sci­ence History.

GILLEN D’ARCY WOOD

It’s been a great plea­sure, Gabrielle. Thank you.

GABRIELLE BIRCHAK

The HMS Chal­lenger sailed for three and a half years to gath­er the ocean’s first glob­al base­line. That record lets us com­pare the 1870s to now, and the changes are unde­ni­able. Deplet­ed big fish, marine heat waves, and microplas­tics from the sur­face to the seafloor.

But this isn’t a eulo­gy. As Gilbert D’Ar­cy Wood says, progress starts when we re-enchant the world, when sea life becomes cen­tral to our sto­ry again. The green turtle’s recov­ery shows what hap­pens when pro­tec­tion meets patience.

Base­lines tell us what we’ve lost. Imag­i­na­tion tells us what we can restore. Chal­lenger was a begin­ning, not an ending.

Gillen’s book is avail­able in the Unit­ed States today, Octo­ber 21st, 2025, and in the UK and Europe in Jan­u­ary 2026. The links to Gillen’s book are in the show notes, in the descrip­tion, and you can also find them at MathScienceHistory.com under the link Tran­scrip­to­ri­um, where we will put the tran­scripts to this pod­cast. Thank you for lis­ten­ing to Math Sci­ence His­to­ry, and until next time, carpe diem.

Thank you for lis­ten­ing to Math Sci­ence His­to­ry. If you enjoyed today’s episode, please leave a rat­ing and a review, because those rat­ings and reviews real­ly help the pod­cast. If you would like to lis­ten to Math Sci­ence His­to­ry with­out the ads on your pod­cast play­er, vis­it us at MathScienceHistory.Supercast.com.

There, you can sign up for a tier, which will give you ear­ly release pod­casts, research notes, bonus mate­r­i­al, and dis­counts on our mer­chan­dise. Also, you can find the tran­scripts at MathScienceHistory.com under the link called Tran­scrip­to­ri­um. And while you’re there, remem­ber to click on that cof­fee but­ton and make a dona­tion, because every sin­gle dol­lar that you donate sup­ports our pro­duc­tion costs and keeps our edu­ca­tion­al web­site free.

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